Flow merging and dividing device and heat exchanger using the device

ABSTRACT

A flow merging and dividing device, wherein two refrigerant flows move from two inlets ( 31, 32 ) located at an inlet part ( 5 ) into a merging part ( 6 ) for merging, the drift of the two refrigerant flows is eliminated by the merging of the flows at the merging part ( 6 ), and the refrigerant flows in which the drift is eliminated by the merging of the flows at the merging part ( 6 ) flows out from three outlets ( 33, 35, 36 ) located at an outlet part ( 7 ), whereby two refrigerant flows can be discharged as three refrigerant flows again from the three outlets ( 33, 35, 36 ) after two refrigerant flows are merged so as to eliminate the drift of the two refrigerant flows.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/JP99/02568 which has an Internationalfiling date of May 18, 1999, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a flow merging and dividing devicewhich merges a plurality of refrigerant flows and then divides the flowand a heat exchanger using the device.

BACKGROUND ART

As shown in FIG. 6, conventional heat exchangers include the oneprovided with a flow dividing device 101 to which a refrigerant flows inat the time of evaporation and a flow merging device 102 from which therefrigerant flows out at the time of evaporation. In this heatexchanger, at the time of evaporation, a refrigerant which flows in fromthe flow dividing device 101 is divided into two paths 103, 105 and therefrigerant is evaporated in each path 103, 105. Then, the tworefrigerant flows 106, 107 from the paths 103, 105 are merged at theflow merging device 102 and are allowed to flow out to a refrigerantpipe 108. It is noted that the flow dividing device 101 functions as aflow merging device for merging a refrigerant at the time ofcondensation and that the flow merging device 102 functions as a flowdividing device for dividing the refrigerant at the time ofcondensation.

FIG. 7 shows another example of heat exchangers. This heat exchanger isprovided with a three-way branched pipe 201 to which a refrigerant flowsin at the time of evaporation and a flow merging device 102 from whichthe refrigerant are discharged at the time of evaporation. In this heatexchanger, the refrigerant which flows in from the three-way branchedpipe 201 at the time of evaporation is divided into two paths 203, 205and the refrigerant is evaporated in each path 203, 205. Then, the tworefrigerant flows 206, 207 are merged at the flow merging device 202 andare allowed to flow out to a refrigerant pipe 208. It is noted that thethree-way branched pipe 201 functions as a flow merging device formerging a refrigerant at the time of condensation and that the flowmerging device 202 functions as a flow dividing device for dividing therefrigerant at the time of condensation.

DISCLOSURE OF THE INVENTION

In the above two examples of conventional heat exchangers, heat exchangeefficiency is improved by providing a plurality of refrigerant paths(multiple paths) . However, there is a problem that, if a refrigerant isnot appropriately distributed into a plurality of paths depending on thethermal load, refrigerant drift is caused and the evaporating ability isdegraded, particularly, in a gas-liquid two-phase flow. This refrigerantdrift is caused when the refrigerant is not distributed to each pathdepending on the thermal load on the air side. In other words, thedistribution ratio of a liquid refrigerant at the time of evaporation ora gas refrigerant at the time of condensation does not match the thermalload on the air side.

Also, even when the refrigerant is appropriately distributed to eachpath depending on the thermal load, the refrigerant cannot beappropriately distributed if the refrigerant flow rate before thedivision of a flow is changed. This is because the change in the flowrate affects the distribution state of the refrigerant.

Thus, it can be suggested that an orifice should be provided toaccelerate the flow so that the change of the distribution state isprevented. In this case, however, there is a problem that pressure lossincreases and refrigerant collision noises occur.

Accordingly, an object of the present invention is to provide a flowmerging and dividing device capable of distributing a refrigerant to aplurality of refrigerant flow paths appropriately at all times tomaximize its heat exchanging ability and a heat exchanger using thedevice.

In order to achieve the above, object, there is provided a heatexchanger having flow merging and dividing means for merging arefrigerant flowing in a plurality of refrigerant flow paths and thendividing the refrigerant to another plurality of refrigerant flow paths.

This heat exchanger has flow merging and dividing means for merging therefrigerant flows which move in a plurality of refrigerant flow pathsand then dividing into another plurality of refrigerant flow paths.Therefore, the refrigerant can be distributed to another plurality ofrefrigerant flow paths appropriately at all times after refrigerantdrift is eliminated by the flow merging and dividing means, and therebythe heat exchanging ability of the heat exchanger can be maximized.

Also, there is provided a flow merging and dividing device comprising:an inlet part having a plurality of inlets; a merging part in which aplurality of refrigerant flows from the plurality of inlets are merged;and an output part having a plurality of outlets to which therefrigerant flows in from the merging part.

In this flow merging and dividing device, a plurality of refrigerantflows move in from a plurality of inlets of the inlet part into themerging part so as to merge. Drift of the plurality of refrigerant flowsis eliminated by this merge at the merging part. Then, the refrigerantflows which have been merged at the merging part to eliminate the driftare discharged from a plurality of outlets of the outlet part. That is,according to this flow merging and dividing device, after a plurality ofrefrigerant flows are merged and the drift is eliminated, therefrigerant can be discharged from a plurality of outlets as a pluralityof refrigerant flows again. Therefore, the refrigerant can bedistributed to a plurality of paths appropriately at all times tomaximize the ability of the heat exchanger by using the flow merging anddividing device of the present invention.

In one embodiment of the present invention, at least an inlet and anoutlet are not opposed to each other.

Since at least an inlet and an outlet are not opposed to each other inthis flow merging and dividing device, a refrigerant drifted from theinlet is prevented from passing through the merging part and flowing outof the outlet as drift. A plurality of refrigerant flows can be reliablymerged at the merging part and the drift of the refrigerant flows can bereliably eliminated.

In one embodiment of the present invention, the flow merging anddividing device further comprises: merging paths for smoothly merging aplurality of refrigerant flows from the plurality of inlets and dividingpaths for smoothly dividing the refrigerant from the merging part towarda plurality of outlets.

In this flow merging and dividing device, the merging paths are used tomerge a plurality of refrigerant flows from a plurality of inletssmoothly and guide them to the merging part. The dividing paths are usedto divide the refrigerant from the merging part smoothly towards aplurality of outlets. Therefore, according to this flow merging anddividing device, the drift of the refrigerant can be prevented withoutcausing any pressure loss. Thus, the ability of the heat exchanger canbe further improved.

Also, there is provided a heat exchanger, wherein a plurality ofrefrigerant flow paths are connected to a plurality of inlets of theflow merging and dividing device and another plurality of refrigerantflow paths are connected to a plurality of outlets of the flow mergingand dividing device.

In this heat exchanger, a plurality of refrigerant flows move in from aplurality of refrigerant flow paths into the flow merging and dividingdevice and the drift is eliminated in this flow merging and dividingdevice. Therefore, the refrigerant can be distributed from this flowmerging and dividing device to another plurality of refrigerant flowpaths appropriately at all times, and thereby the heat exchangingability can be maximized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a view showing an axial end surface of a flow merging anddividing device according to a first embodiment of the invention;

FIG. 1B is a view showing a half cross section of the first embodiment;

FIG. 1C is a view showing the other end surface of the first embodiment;

FIG. 1D is a sectional view showing a state that branch pipes areconnected to the first embodiment;

FIG. 2A is a view showing an axial end surface of a flow merging anddividing device according to a second embodiment of the invention;

FIG. 2B is a view showing a half cross section of the second embodiment;

FIG. 2C is a view showing the other end surface of the secondembodiment;

FIG. 2D is a view showing a side surface of a branch pipe connectingmember of the second embodiment;

FIG. 2E is a sectional view showing a state that branch pipes areconnected to the second embodiment;

FIG. 3A shows a structure of a heat exchanger according to a thirdembodiment of the invention;

FIG. 3B is an end view showing a flow merging and dividing device in theheat exchanger;

FIG. 4 is a view showing a structure of a heat exchanger according to afourth embodiment of the invention;

FIG. 5A is a schematic view showing a modification of the flow mergingand dividing device of the invention;

FIG. 5B is a schematic view showing another modification;

FIG. 5C is a schematic view showing another modification;

FIG. 6 is a view showing a structure of a conventional heat exchanger;and

FIG. 7 is a view showing a structure of another conventional heatexchanger.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the flow merging and dividing device of the presentinvention will be described in detail below with reference to drawings.

First Embodiment

FIG. 1 shows a first embodiment of the flow merging and dividing deviceof the present invention. As shown in FIG. 1B, this flow merging anddividing device is constituted such that branch pipe connecting members2, 3 are internally engaged to both axial end parts 1A, 1B of acylindrical-shape outer pipe 1 made of copper of which approximatecentral part in the axial direction is slightly constricted. The endpart 1A of the outer pipe 1 and the branch pipe connecting member 2constitute an inlet part 5. The central part 1C of the outer pipe 1constitutes a merging part 6. The end part 1B of the outer pipe 1constitutes an outlet part 7. Parts 1D, 1E widening from the centralpart 1C of the outer pipe 1 towards the end parts 1A, 1B constitute amerging path 22 and a dividing path 23.

As shown in FIG. 1A, the branch pipe connecting member 2 has two axialthrough trenches 8, 10. These two through trenches 8, 10 are disposed180° off each other in the circumferential direction. The throughtrenches 8, 10 constitute two inlets. The branch pipe connecting member2 is fixed to the outer pipe 1 by riveting an outer periphery of the endpart 1A of the outer pipe 1 at two sites 11, 12 on the outer peripheralsurface which are disposed 90° off the two through trenches 8, 10.

As shown in FIG. 1C, the branch pipe connecting member 3 has three axialthrough trenches 15, 16, 17. These three axial through trenches 15, 16,17 are disposed 120° off each other. The through trenches 15, 16, 17constitute three outlets. The branch pipe connecting member 3 is fixedto the outer pipe 1 by riveting an outer periphery of the end part 1B ofthe outer pipe 1 at three Asites 20, 21, 22 on the outer peripheralsurface which are 60° off the three through trenches 15, 16, 17. Asevident in FIGS. 1A and 1C, the through trenches 8, 10 of the inlet part5 are not opposed to the through trenches 15, 16, 17 of the outlet part7, but their positions are off each other in the circumferentialdirection.

As shown in FIG. 1D, a branch pipe 25 is internally engaged to thethrough trench 10 of the branch pipe connecting member 2 in the inletpart 5 as a refrigerant pipe. Another branch pipe having the samestructure as that of this branch pipe 25 is internally engaged to theother through trench 8 though it is not shown in the figure. On theother hand, branch pipes 26, 27 are internally engaged to the throughtrenches 15, 17 of the branch pipe connecting member 3 in the outletpart 7 as refrigerant pipes. Another branch pipe having the samestructure as that of the branch pipes 26, 27 is internally engaged tothe other through trench 16 as a refrigerant pipe though it is not shownin the figure.

In the flow merging and dividing device constituted as described above,two refrigerant flows move from two inlets 31, 32 of the inlet part 5into the merging part 6 and merge. The drift of the two refrigerantflows is eliminated by this merge at the merging part 6. Then,refrigerant flows which have been merged to eliminate the drift at themerging part 6 are discharged from three outlets 33, 35, 36 of theoutlet part 7. That is, according to this flow merging and dividingdevice, after the two refrigerant flows are merged and the drift iseliminated, the refrigerant can be discharged from three outlets 33, 35,36 as three refrigerant flows again without any drift. Therefore, a heatexchanger having an enhanced heat exchanging ability which candistribute the refrigerant to a plurality of paths appropriately at alltime can be constituted by using this flow merging and dividing device.

Also, since the two inlets 31, 32 are not opposed to the three outlets33, 35, 36 in this flow merging and dividing device, the refrigerantflows drifted from the inlets 31, 32 are prevented from passing throughthe merging part 6 and flowing out of the outlets 33, 35, 36 as drift.Therefore, the two refrigerant flows can be reliably merged at themerging part 6 and the drift of the refrigerant flows can be reliablyeliminated.

Also, in this flow merging and dividing device, the merging path 22 canbe used to merge two refrigerant flows from the two inlets 31, 32smoothly and guide them to the merging part 6. The dividing path 23 canbe used to divide the refrigerant from the merging part 6 toward threeoutlets 33, 35, 36 smoothly. Thus, according to this flow merging anddividing device, the drift of the refrigerant can be prevented withoutcausing any pressure loss, and thereby the ability of the heat exchangercan be further improved.

Second Embodiment

FIG. 2 shows a second embodiment of the flow merging and dividing deviceof the present invention. The second embodiment is different from thefirst embodiment shown in FIG. 1 only in the next point (i).

(i) As shown in FIGS. 2B, 2D and 2E, a protruded part 41 in a conicalshape is formed in the approximate central part of an axial end surface2A of a branch pipe connecting member 2. Also, a protruded part 42 in aconical shape is formed in an approximate central part of an axial endsurface 3A of a branch pipe connecting member 3. The axial dimension ofthe protruded parts 41, 42 is smaller than the axial dimension of amerging path 22 and the dividing path 23.

According to the second embodiment, a tapered surface 41A of theprotruded part 41 and a tapered surface 1D-1 of a part 1D wideningtoward the end constitute a merging path 43. A tapered surface 42A ofthe protruded part 42 and a tapered surface 1E-1 of a part 1E wideningtoward the end constitute a dividing path 45. As is evident fromcomparison between FIG. 1D and FIG. 2E, according to the merging path 43the second embodiment, the tapered surface 41A can be utilized to mergeinflow refrigerant flows more smoothly than the merging path 22 of thefirst embodiment. Also, according to the dividing path 45, the taperedsurface 42A can be utilized to divide the merged refrigerant moresmoothly than the dividing path 23 of the first embodiment. Therefore,according to the second embodiment, pressure loss can be furtherdecreased and a more efficient heat exchanger can be constitutedcompared with the first embodiment.

The branch pipes 25, 26, 27 are insert and soldered to the branch pipeconnecting members 2, 3 in the above first and second embodiments. It isnoted, however, that three holes 302A and two holes 303A may be formedin end walls 302, 303, respectively, of both axial ends of a cylindricalmember 301 as shown in FIG. 5C. Three branch pipes 305 communicatingwith the three holes 302A of the end wall 302 may be welded to the endwall 302 and two branch pipes 306 communicating with the two holes 303Aof the end wall 303 may be welded to the end wall 303.

Also, flow dividing devices 311, 312 may be connected to both ends of aconnecting pipe 310 to constitute a flow merging and dividing device 313as shown in FIG. 5A. The flow dividing devices 311, 312 have alarge-diameter part 311A, 312A and a small-diameter part 311B, 312B. Thelarge-diameter part 311A, 312A and the small-diameter part 311B, 312Bare connected with a gentle slope. Two branch pipes 315, 316 areconnected and communicated with an end surface 313 of the large-diameterpart 311A. Other two branch pipes 317, 318 are connected andcommunicated with an end surface 315 of the large-diameter part 312A. Inthis flow merging and dividing device 313, the two flow dividing devices311, 312 and the connecting pipe 310 constitute a merging part and theend surfaces 313, 315 of the flow dividing devices 311, 312 constitutean inlet part and an outlet part, respectively. The communicating holes313A, 313B of the end surface 313 constitute inlets and thecommunicating holes 315A, 315B of the end surface 315 constituteoutlets. The communicating holes 313A, 313B are not opposed to thecommunicating holes 315A, 315B.

Further, as shown in FIG. 5B, branched pipes 321, 322 may be connectedto both ends of a connecting pipe 320 to constitute a flow merging anddividing device 323. The branched pipes 321, 322 have two branches each,that is, branch parts 324, 325 and branch parts 326, 327. Branch pipes328, 330 are connected to the branch parts 324, 325 and branch pipes331, 332 are connected to the branch parts 326, 327. In the flow mergingand dividing device 323 of this constitution, base parts 321A, 322A ofthe branched pipes 321, 322 and a connecting pipe 320 constitute amerging part. The branch parts 324, 325 of the branched pipe 321constitute an inlet part and the branch parts 326, 327 of the branchedpipe 322 constitute an outlet part.

Also, there are three or less inlets or outlets in the above-describedflow merging and dividing device, but there may be three or more ofthese.

Third Embodiment

FIG. 3 shows a side view of a heat exchanger according to a thirdembodiment of the present invention. This heat exchanger uses a flowmerging and dividing device 50 using a branch pipe connecting member 54in the same constitution as the branch pipe connecting member 2 (seeFIG. 3B) instead of the branch pipe connecting member 3 in the flowmerging and dividing device of the first embodiment. Two throughtrenches 65, 66 of this branch pipe connecting member 54 are disposed90° off the two through trenches 8, 10 of the branch pipe connectingmember 2 in the circumferential direction.

In this heat exchanger, a plurality of fin plates 51 bent at an acuteangle are disposed at predetermined intervals in the directionperpendicular to the plane of the paper. A refrigerant pipe 52penetrates across the plurality of fin plates 51.

Also, this heat exchanger has a flow dividing device 53. This flowdividing device 53 is connected to one opening 55A of a firstrefrigerant flow path 55 and one opening 56A of a second refrigerantflow path 56 by a branch pipe 57. The first refrigerant flow path 55 isextended penetrating the plurality of fin plates 51 like a needleworkalong the outer periphery side of a longer bent part 64 of the fin plate51. The other opening 55B of the first refrigerant flow path 55 isconnected to one inlet 65 of an inlet part 59 of the flow merging anddividing device 50 by a branch pipe 60.

On the other hand, the second refrigerant flow path 56 is extended alongthe outer periphery side of a shorter bent part 67 of the fin plate 51and then along the inner periphery side after turning at the end part67A. The other opening 56B of this second refrigerant flow path 56 isconnected to the other inlet 66 of the inlet part 59 of the flow mergingand dividing device 50 by a branch pipe 68. This flow merging anddividing device 50 is disposed between the longer bent part 64 and theshorter bent part 67 of the fin plate 51.

An outlet part 70 of the flow merging and dividing device 50 has twooutlets 71, 72 constituted by the through trenches 8, 10. The outlet 71is connected to one opening 75A of a third refrigerant flow path 75 viaa branch pipe 73. The third refrigerant flow path 75 is extended alongthe inner periphery side of the bent part 64 and the other opening 75Blocated slightly lower than the center of the bent part 64 is connectedto one opening 77A of a branched pipe 77 by a branch pipe 76.

The other outlet 72 of the flow merging and dividing device 50 isconnected to one opening 80A of a fourth refrigerant flow path 80 via abranch pipe 78. The fourth refrigerant flow path 80 is extended upwardalong the inner periphery side after turning near the lower end of thebent part 56 and the other opening 80B located slightly lower than thecenter of the bent part 64 is connected to the other opening 77B of abranched pipe 77 by a branch pipe 81.

According to the heat exchanger constituted as described above, onerefrigerant flow moves from the flow dividing device 53 to the firstrefrigerant flow path 55, the branch pipe 60 and the through trench(inlet) 65 of the flow merging and dividing device 50 at the time ofevaporation. The other refrigerant flow from the flow dividing device 53moves to the second refrigerant flow path 56, the branch pipe 68 and thethrough trench (inlet) 66 of the flow merging and dividing device 50.These two refrigerant flows are merged at the merging part 6 of the flowmerging and dividing device 50 and the drift is eliminated.Subsequently, the refrigerant in the merging part 6 flows from theoutlets 71, 72 of the outlet part 70 via the branch pipes 73, 78 andpasses through the third refrigerant flow path 75 and the fourthrefrigerant flow path 80. Then the refrigerant flows into the openings77A, 77B of the branched pipe 77 via branch pipes 76, 81.

On the other hand, at the time of condensation, the refrigerant flowfrom one opening 77A of the branched pipe 77 flows into the outlet 71 ofthe outlet part 70 via the branch pipe 76, the third refrigerant flowpath 75 and the branch pipe 73. The refrigerant flow from the otheropening 77B of the branched pipe 77 flows into the outlet 72 of theoutlet part 70 via the branch pipe 81, the fourth refrigerant flow path80 and the branch pipe 78. These two refrigerant flows are merged at themerging part 6 of the flow merging and dividing device 50 and the driftis eliminated. Subsequently, the refrigerant in the merging part 6 flowsfrom the through trenches 65, 66 of the inlet part 59, passes throughthe branch pipes 60, 68 and then flows into the first and secondrefrigerant flow paths 55, 56.

Thus, according to the heat exchanger of this embodiment, the drift ofthe refrigerant from the first and second refrigerant flow paths 55, 56or the third and fourth refrigerant flow paths 75, 80 can be eliminatedby the flow merging and dividing device 50 provided between the firstand second refrigerant flow paths 55, 56 and the third and fourthrefrigerant flow paths 75, 80. Therefore, the refrigerant can bedistributed appropriately at all times to the third and fourthrefrigerant flow paths 75, 80 or the first and second refrigerant flowpaths 55, 56. Thus, the heat exchanging ability can be maximized.

Fourth Embodiment

FIG. 4 shows a side view of a heat exchanger according to a fourthembodiment of the present invention. This heat exchanger uses the flowmerging and dividing device 50 provided in the third embodiment. Also,this heat exchanger is provided with fin plates 51 provided in the thirdembodiment. A refrigerant pipe 90 penetrates the fin plates 51 in thedirection perpendicular to the plane of the paper.

In this heat exchanger, one opening pipe 91 is connected to one opening90A of the refrigerant pipe 90 before branching. The other opening 90Bof this refrigerant pipe 90 is connected to a first opening 92A of athree-way branched pipe 92. A second opening 92B of the three-waybranched pipe 92 is connected to one opening 93A of a first refrigerantflow path 93 and a third opening 92C is connected to one opening 95A ofa second refrigerant flow path 95.

The first refrigerant flow path 93 is extended penetrating the pluralityof fin plates 51 like a needlework along a longer bent part 64 of thefin plate 51. The other opening 93B of the first refrigerant flow path93 is connected to one through trench 65 of an inlet part 59 of the flowmerging and dividing device 50 by a branch pipe 60. On the other hand,the second refrigerant flow path 95 is extended from the upper end partof the longer bent part 64 of the fin plate 51 over the upper end of ashorter bent part 67 of the fin plate 51 and further along the outerperiphery side of this bent part 67. The other opening 95B of thissecond refrigerant flow path 95 located in the vicinity of the lower endof the shorter bent part 67 is connected to the other through trench 66of the inlet part 59 of the flow merging and dividing device 50 by abranch pipe 96.

An outlet part 70 the flow merging and dividing device 50 has twooutlets constituted by the through trenches 8, 10. The outletconstituted by the through trench 8 is connected to one opening 80A of athird refrigerant flow path 80 via a branch pipe 78. The thirdrefrigerant flow path 80 is extended along the inner periphery side ofthe bent part 64 and the other opening 80B located slightly lower thanthe center of the bent part 64 is connected to one opening 77B of abranched pipe 77 by a branch pipe 81.

The other outlet 71 of the flow merging and dividing device 50 isconnected to one opening 98A of a fourth refrigerant flow path 98 via abranch pipe 97. The fourth refrigerant flow path 98 is connected to arefrigerant pipe 90 in the vicinity of the center of the bent part 64 bya gangway pipe 99 from the vicinity of the upper end of the bent part 67and the other opening 98B is connected to the other opening 77A of abranched pipe 77 by a branch pipe 100.

According to the heat exchanger constituted as described above,refrigerant flows divided to the first refrigerant flow path 93 and thesecond refrigerant flow path 95 can be merged in the flow merging anddividing device 50 at the time of evaporation. Then, the refrigerantflow of which drift has been eliminated by this merge can be divided tothe third refrigerant flow path 80 and the fourth refrigerant flow path98. On the other hand, at the time of condensation, the refrigerantflows divided to the third refrigerant flow path 80 and the fourthrefrigerant flow path 98 can be merged in the flow merging and dividingdevice 50. Then, the refrigerant flow of which drift has been eliminatedby this merge can be divided to the first refrigerant flow path 93 andthe second refrigerant flow path 95.

Thus, according to this embodiment, the drift of the refrigerant fromthe first and second refrigerant flow paths 93, 95 or the third andfourth refrigerant flow paths 80, 98 can be eliminated by the flowmerging and dividing device 50. Therefore, the refrigerant can bedistributed appropriately at all times to the third and fourthrefrigerant flow paths 80, 98 or the first and second refrigerant flowpaths 93, 95. Thus, the heat exchanging ability can be maximized.

It is noted that the present invention can be applied in a heatexchanger of outdoor equipment although the heat exchangers of indoorequipment are described in the third and fourth embodiments.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a heat exchanger having aplurality of refrigerant flow paths and is useful in distributing arefrigerant to the plurality of refrigerant flow paths appropriately atall times to maximize the heat exchanging ability.

What is claimed is:
 1. A flow merging and dividing device comprising: anouter pipe, said outer pipe including a first end and a second end; aninlet portion having a plurality of inlets, said inlet portionconstituting said first end and a first branch pipe connecting member; amerging portion for merging a plurality of refrigerant flows from saidplurality of inlets; and an output portion having a plurality ofoutlets, said output portion constituting said second end and a secondbranch pipe connecting member, wherein said refrigerant flows out fromsaid merging portion and into said output portion.
 2. The flow mergingand dividing device according to claim 1, wherein said plurality ofinlets and said plurality of outlets are not opposed to each other. 3.The flow merging and dividing device according to claim 1, wherein saidfirst branch pipe connecting member further comprises two axial throughtrenches.
 4. The flow merging and dividing device according to claim 3,wherein said through trenches are disposed 180° from each other in acircumferential direction.
 5. The flow merging and dividing deviceaccording to claim 4, wherein said through trenches constitute twoinlets.
 6. The flow merging and dividing device according to claim 1,wherein said second branch pipe connecting member further comprisesthree axial through trenches.
 7. The flow merging and dividing deviceaccording to claim 6, wherein said through trenches are disposed 120°from each other in a circumferential direction.
 8. The flow merging anddividing device according to claim 7, wherein said through trenchesconstitute three outlets.
 9. The flow merging and dividing deviceaccording to claim 1, wherein said first and second branch pipeconnecting members are fixed to said first and second ends by rivetingan outer periphery of the outer pipe.
 10. The flow merging and dividingdevice according to claim 1, further comprising: merging paths forsmoothly merging said plurality of refrigerant flows from said pluralityof inlets; and dividing paths for smoothly dividing the refrigerant fromsaid merging portion toward said plurality of outlets.
 11. The flowmerging and dividing device according to claim 10, wherein said mergingpaths further comprise a protruded part, said protruded part is conicalin shape and formed approximately in a central portion of said firstbranch pipe connecting member.
 12. The flow merging and dividing deviceaccording to claim 10, wherein said dividing paths further comprise aprotruded part, said protruded part is conical in shape and formedapproximately in a central portion of said second branch pipe connectingmember.